Currently, the commonly used display apparatus includes Liquid Crystal Display (LCD) display apparatus and Organic Light-Emitting Diode (OLED) display apparatus. Both LCD display apparatus and OLED display apparatus include array substrates. The array substrate includes a plurality of Thin Film Transistors (TFTs)
With the continuous innovation of the semiconductor design and manufacturing technologies, the continuous improvement of device speed and continuous increase of size and resolution of the display panel, the occupy area of the TFTs has become more important than ever, especially in oxide TFTs.
An oxide TFT usually includes a gate formed over a substrate, a gate dielectric layer covering the gate, an active layer formed over the gate dielectric layer, an etching stop layer formed over the active layer, a source contact through-hole and a drain contact through-holes respectively penetrating through the gate dielectric layer; and a source and a drain connecting with the active layer. The channel of the TFT in the active layer in such a TFT is referred as a lateral channel.
The source contact through-hole and the drain contact through-holes are formed in a same layer. Thus, the source contact through-hole and the drain contact through-hole have to have a required distance because of the limitation of the etching process for forming the source contact through-hole and the drain contact through-hole. The required distance can prevent the source contact through-hole and the drain contact through-hole from being penetrated through during the etching process. If the source contact through-hole and the drain contact through-hole are penetrated through during the etching process, the TFT would fail.
The required distance between the source contact through-hole and the drain contact through-hole is referred as the width of the channel of the TFT in the active layer. Further, the required distance is also related to the size of the TFT. Thus, the size of the oxide TFT is relatively large because of the required distance.
Further, because the gate is formed in a different layer from the source and the drain, a parasitic capacitance may be generated between the gate and the source and between the gate and drain. Thus, the display effect of a display apparatus having such oxide TFTs may not meet the desired requirements. The disclosed device structures, methods and systems are directed to at least partially solve one or more problems set forth above and other problems.